1. Technical Field
The invention relates to an image data restoration apparatus and an image data restoration method for restoring still image data acquired by capturing a subject image by means of an imaging element, and also relates to an imaging apparatus provided with the image data restoration apparatus and a computer readable medium storing an image data restoration program.
2. Description of the Related Art
In general, there is an image processing apparatus photoelectrically converts a subject image and arithmetically processes the image using an arithmetic device such as a computer. Using this image processing apparatus, various techniques/apparatuses have been proposed for restoring degradation of an image due to camera shake or the like upon image capturing. In this image restoration processing, blurring or spread of one point of an image, which leads to deterioration of the image, into its surrounding image is mathematically handled as a spread function so that arithmetic processing can be done.
For example, JP Hei.6-118468 A (corresponding to U.S. Pat. No. 5,365,303) discloses a method for recovering non-blurred image data by extrapolating missing data to find a pseudo inverse matrix of a blur matrix, which is a matrix expression of a spread function, and by multiplying the pseudo inverse matrix and blurred image data.
However, since the method of JP Hei.6-118468 A extrapolates the missing data, noise may occur in the recovered image data and image quality may be degraded. JP Hei.6-118468 A does not mention about a countermeasure against this noise at all. If nothing is done for the noise, a good restored image may not be achieved.
When a blurred image is restored, complex filter processing is required in proportion to a pixel range to which the influence of blurring extends. There is a room for improvement in that the processing burden on a computer that executes the image processing and that the processing takes long time.